Problem with TFT Touch Screen and Arduino Mega

I bought the Arduino Mega and the TFT Touch Screen (V2.1) last week and it won’t run any demo.
I downloaded the files and installed the library. Everything’s hooked up and powers up OK.
The example files compile and upload to the Arduino OK (at least the lights flash on the Arduino and there’s no error message in the IDE) but there’s no response on the screen.
I tried several of the examples and only see a blank screen (the back light works but no image on the screen).
Do I need to alter some definitions for it to work with the Mega?
Should I expect it to work out-of-the-box?